They do look uncomfortable, but they are not. You get used to wearing them very quickly.
Assuming you mean "g"-string, then yes, I do wear one on occasion. They are really fun at the beach or pool and definitely attract a lot of attention. They aren't for the shy, that's for sure.
I often wear thong swimsuits at the beach or pool. They are great fun, but they do attract a lot of attention.
Some definitely do, but my guess is they are in the minority.